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[ 4 / 4 ] Application profile is long enough (43.37 s)
To have good quality measurements, it is advised that the application profiling time is greater than 10 seconds.
[ 3 / 3 ] Most of time spent in analyzed modules comes from functions with source/debug info
-g option gives access to debugging informations, such are source locations.
[ 0 / 3 ] Architecture specific options are unknown for some functions (compilation options info are not available)
Architecture specific options are needed to produce efficient code for a specific processor ( -march=(target) ).
Architecture specific options are needed to produce efficient code for a specific processor ( -x(target), -ax(target) or -march=(target)).
[ 0 / 3 ] Most of time spent in analyzed modules comes from functions without compilation options informations
Functions without compilation options information cumulate 95.01% of the time spent in analyzed modules. For exec, check that both -g and -grecord-gcc-switches are present. Remark: if such options are indeed used, this can also be due to some compiler built-in functions (typically math) or statically linked libraries. This warning can be ignored in that case.
[ 0 / 3 ] Optimization level is unknown for some functions (compilation options info are not available)
To have better performances, it is advised to help the compiler by using a proper optimization level (-O2 of higher). Warning, depending on compilers, faster optimization levels can decrease numeric accuracy.
[ 3 / 3 ] Host configuration allows retrieval of all necessary metrics.
[ 2 / 2 ] Application is correctly profiled ("Others" category represents 0.14 % of the execution time)
To have a representative profiling, it is advised that the category "Others" represents less than 20% of the execution time in order to analyze as much as possible of the user code
[ 1 / 1 ] Lstopo present. The Topology lstopo report will be generated.
[ 4 / 4 ] Enough time of the experiment time spent in analyzed loops (94.89%)
If the time spent in analyzed loops is less than 30%, standard loop optimizations will have a limited impact on application performances.
[ 3 / 4 ] A significant amount of threads are idle (23.51%)
On average, more than 10% of observed threads are idle. Such threads are probably IO/sync waiting. Some hints: use faster filesystems to read/write data, improve parallel load balancing and/or scheduling.
[ 4 / 4 ] CPU activity is good
CPU cores are active 99.41% of time
[ 4 / 4 ] Loop profile is not flat
At least one loop coverage is greater than 4% (6.26%), representing an hotspot for the application
[ 4 / 4 ] Enough time of the experiment time spent in analyzed innermost loops (94.72%)
If the time spent in analyzed innermost loops is less than 15%, standard innermost loop optimizations such as vectorisation will have a limited impact on application performances.
[ 4 / 4 ] Affinity is good (99.38%)
Threads are not migrating to CPU cores: probably successfully pinned
[ 3 / 3 ] Less than 10% (0.00%) is spend in BLAS1 operations
It could be more efficient to inline by hand BLAS1 operations
[ 0 / 3 ] Too many functions do not use all threads
Functions running on a reduced number of threads (typically sequential code) cover at least 10% of application walltime (14.62%). Check both "Max Inclusive Time Over Threads" and "Nb Threads" in Functions or Loops tabs and consider parallelizing sequential regions or improving parallelization of regions running on a reduced number of threads
[ 3 / 3 ] Cumulative Outermost/In between loops coverage (0.16%) lower than cumulative innermost loop coverage (94.72%)
Having cumulative Outermost/In between loops coverage greater than cumulative innermost loop coverage will make loop optimization more complex
[ 2 / 2 ] Less than 10% (0.00%) is spend in BLAS2 operations
BLAS2 calls usually could make a poor cache usage and could benefit from inlining.
[ 2 / 2 ] Less than 10% (0.00%) is spend in Libm/SVML (special functions)
| Loop ID | Analysis | Penalty Score |
|---|---|---|
| ►Loop 61 - exec | Execution Time: 6 % - Vectorization Ratio: 100.00 % - Vector Length Use: 100.00 % | |
| ►Loop Computation Issues | 8 | |
| ○ | [SA] Presence of expensive FP instructions - Perform hoisting, change algorithm, use SVML or proper numerical library or perform value profiling (count the number of distinct input values). There are 2 issues (= instructions) costing 4 points each. | 8 |
| ►Data Access Issues | 2 | |
| ○ | [SA] More than 20% of the loads are accessing the stack - Perform loop splitting to decrease pressure on registers. This issue costs 2 points. | 2 |
| ►Loop 220 - exec | Execution Time: 5 % - Vectorization Ratio: 100.00 % - Vector Length Use: 100.00 % | |
| ►Loop Computation Issues | 12 | |
| ○ | [SA] Presence of expensive FP instructions - Perform hoisting, change algorithm, use SVML or proper numerical library or perform value profiling (count the number of distinct input values). There are 2 issues (= instructions) costing 4 points each. | 8 |
| ○ | [SA] Less than 10% of the FP ADD/SUB/MUL arithmetic operations are performed using FMA - Reorganize arithmetic expressions to exhibit potential for FMA. This issue costs 4 points. | 4 |
| ►Loop 59 - exec | Execution Time: 5 % - Vectorization Ratio: 100.00 % - Vector Length Use: 100.00 % | |
| ►Loop Computation Issues | 8 | |
| ○ | [SA] Presence of expensive FP instructions - Perform hoisting, change algorithm, use SVML or proper numerical library or perform value profiling (count the number of distinct input values). There are 2 issues (= instructions) costing 4 points each. | 8 |
| ►Loop 67 - exec | Execution Time: 5 % - Vectorization Ratio: 100.00 % - Vector Length Use: 100.00 % | |
| ►Loop Computation Issues | 4 | |
| ○ | [SA] Presence of expensive FP instructions - Perform hoisting, change algorithm, use SVML or proper numerical library or perform value profiling (count the number of distinct input values). There are 1 issues (= instructions) costing 4 points each. | 4 |
| ►Loop 111 - exec | Execution Time: 4 % - Vectorization Ratio: 100.00 % - Vector Length Use: 100.00 % | |
| ►Loop Computation Issues | 4 | |
| ○ | [SA] Presence of expensive FP instructions - Perform hoisting, change algorithm, use SVML or proper numerical library or perform value profiling (count the number of distinct input values). There are 1 issues (= instructions) costing 4 points each. | 4 |
| ►Loop 127 - exec | Execution Time: 4 % - Vectorization Ratio: 26.85 % - Vector Length Use: 15.86 % | |
| ►Loop Computation Issues | 39 | |
| ○ | [SA] Presence of expensive FP instructions - Perform hoisting, change algorithm, use SVML or proper numerical library or perform value profiling (count the number of distinct input values). There are 8 issues (= instructions) costing 4 points each. | 32 |
| ○ | [SA] Presence of a large number of scalar integer instructions - Simplify loop structure, perform loop splitting or perform unroll and jam. This issue costs 2 points. | 2 |
| ○ | [SA] Peel/tail loop, considered having a low iteration count - Perform full unroll. Force compiler to use masked instructions. This issue costs 5 points. | 5 |
| ►Control Flow Issues | 25 | |
| ○ | [SA] Too many paths (16 paths) - Simplify control structure. There are 16 issues ( = paths) costing 1 point each with a malus of 4 points. | 20 |
| ○ | [SA] Peel/tail loop, considered having a low iteration count - Perform full unroll. Force compiler to use masked instructions. This issue costs 5 points. | 5 |
| ►Data Access Issues | 30 | |
| ○ | [SA] Presence of special instructions executing on a single port (INSERT/EXTRACT, BLEND/MERGE, SHUFFLE/PERM) - Simplify data access and try to get stride 1 access. There are 28 issues (= instructions) costing 1 point each. | 28 |
| ○ | [SA] More than 20% of the loads are accessing the stack - Perform loop splitting to decrease pressure on registers. This issue costs 2 points. | 2 |
| ►Vectorization Roadblocks | 20 | |
| ○ | [SA] Too many paths (16 paths) - Simplify control structure. There are 16 issues ( = paths) costing 1 point each with a malus of 4 points. | 20 |
| ►Inefficient Vectorization | 30 | |
| ○ | [SA] Presence of special instructions executing on a single port (INSERT/EXTRACT, BLEND/MERGE, SHUFFLE/PERM) - Simplify data access and try to get stride 1 access. There are 28 issues (= instructions) costing 1 point each. | 28 |
| ○ | [SA] Inefficient vectorization: use of masked instructions - Simplify control structure. The issue costs 2 points. | 2 |
| ►Loop 123 - exec | Execution Time: 4 % - Vectorization Ratio: 100.00 % - Vector Length Use: 100.00 % | |
| ►Loop Computation Issues | 8 | |
| ○ | [SA] Presence of expensive FP instructions - Perform hoisting, change algorithm, use SVML or proper numerical library or perform value profiling (count the number of distinct input values). There are 2 issues (= instructions) costing 4 points each. | 8 |
| ►Loop 182 - exec | Execution Time: 4 % - Vectorization Ratio: 100.00 % - Vector Length Use: 100.00 % | |
| ►Loop Computation Issues | 4 | |
| ○ | [SA] Less than 10% of the FP ADD/SUB/MUL arithmetic operations are performed using FMA - Reorganize arithmetic expressions to exhibit potential for FMA. This issue costs 4 points. | 4 |
| ►Loop 115 - exec | Execution Time: 4 % - Vectorization Ratio: 99.08 % - Vector Length Use: 82.65 % | |
| ►Loop Computation Issues | 48 | |
| ○ | [SA] Presence of expensive FP instructions - Perform hoisting, change algorithm, use SVML or proper numerical library or perform value profiling (count the number of distinct input values). There are 12 issues (= instructions) costing 4 points each. | 48 |
| ►Control Flow Issues | 20 | |
| ○ | [SA] Too many paths (16 paths) - Simplify control structure. There are 16 issues ( = paths) costing 1 point each with a malus of 4 points. | 20 |
| ►Data Access Issues | 97 | |
| ○ | [SA] Presence of expensive instructions (GATHER/SCATTER) - Use array restructuring. There are 20 issues (= instructions) costing 4 points each. | 80 |
| ○ | [SA] Presence of special instructions executing on a single port (BLEND/MERGE, BROADCAST) - Simplify data access and try to get stride 1 access. There are 15 issues (= instructions) costing 1 point each. | 15 |
| ○ | [SA] More than 20% of the loads are accessing the stack - Perform loop splitting to decrease pressure on registers. This issue costs 2 points. | 2 |
| ►Vectorization Roadblocks | 20 | |
| ○ | [SA] Too many paths (16 paths) - Simplify control structure. There are 16 issues ( = paths) costing 1 point each with a malus of 4 points. | 20 |
| ►Inefficient Vectorization | 97 | |
| ○ | [SA] Presence of expensive instructions (GATHER/SCATTER) - Use array restructuring. There are 20 issues (= instructions) costing 4 points each. | 80 |
| ○ | [SA] Presence of special instructions executing on a single port (BLEND/MERGE, BROADCAST) - Simplify data access and try to get stride 1 access. There are 15 issues (= instructions) costing 1 point each. | 15 |
| ○ | [SA] Inefficient vectorization: use of masked instructions - Simplify control structure. The issue costs 2 points. | 2 |
| ►Loop 89 - exec | Execution Time: 3 % - Vectorization Ratio: 19.47 % - Vector Length Use: 14.93 % | |
| ►Loop Computation Issues | 31 | |
| ○ | [SA] Presence of expensive FP instructions - Perform hoisting, change algorithm, use SVML or proper numerical library or perform value profiling (count the number of distinct input values). There are 6 issues (= instructions) costing 4 points each. | 24 |
| ○ | [SA] Presence of a large number of scalar integer instructions - Simplify loop structure, perform loop splitting or perform unroll and jam. This issue costs 2 points. | 2 |
| ○ | [SA] Peel/tail loop, considered having a low iteration count - Perform full unroll. Force compiler to use masked instructions. This issue costs 5 points. | 5 |
| ►Control Flow Issues | 25 | |
| ○ | [SA] Too many paths (16 paths) - Simplify control structure. There are 16 issues ( = paths) costing 1 point each with a malus of 4 points. | 20 |
| ○ | [SA] Peel/tail loop, considered having a low iteration count - Perform full unroll. Force compiler to use masked instructions. This issue costs 5 points. | 5 |
| ►Data Access Issues | 2 | |
| ○ | [SA] More than 20% of the loads are accessing the stack - Perform loop splitting to decrease pressure on registers. This issue costs 2 points. | 2 |
| ►Vectorization Roadblocks | 20 | |
| ○ | [SA] Too many paths (16 paths) - Simplify control structure. There are 16 issues ( = paths) costing 1 point each with a malus of 4 points. | 20 |
| ►Inefficient Vectorization | 2 | |
| ○ | [SA] Inefficient vectorization: use of masked instructions - Simplify control structure. The issue costs 2 points. | 2 |